This invention relates to motor vehicle ignition lock cylinder and gear shift lever interlock systems. More particularly, it relates to systems which inhibit the removal of the key from the ignition lock cylinder when the gear shift lever is out of a predetermined park position and which further inhibit the movement of the gear shift lever out of the predetermined park position unless the key is in the ignition lock cylinder and inhibited from removal.
Prior art systems are well known which perform these functions by mechanical means linking gear shift levers and ignition lock cylinders. Most modern day automobiles have an ignition lock cylinder mounted to the steering column and a column mounted shift gear shift lever or console mounted gear shift lever. Ignition lock cylinders commonly have an OFF/LOCK position whereat key insertion and removal are performed and the vehicle accessories and engine are not powered; a RUN position whereat key removal is inhibited and the vehicle accessories and engine are powered; and, an intermediate ACCESSORY position whereat key removal is inhibited and the vehicle accessories are powered but the vehicle engine is not.
Furthermore, mechanical linkages are widely used to inhibit gear shift lever movement out of a predetermined park position--park in automatic transmission equipped vehicles and reverse in manual transmission equipped vehicles--unless the ignition lock cylinder is out of the OFF/LOCK position and ignition key removal is inhibited. Also, the ignition lock cylinder is inhibited from returning to the OFF/LOCK position if the gear shift lever remains out of the predetermined park position thereby ensuring return to park position before ignition key removal and cylinder lock-up.
Column mounted gear shift lever equipped vehicles may employ a mechanical blocking means to inhibit shift lever movement out of the park position when the ignition lock cylinder is in the OFF/LOCK position or rotation of the ignition lock cylinder into the OFF/LOCK position when the shift lever is out of the park position. Other column mounted gear shift lever equipped vehicles may employ a flexible cable between the shift lever and a neutral start switch to electrically inhibit engine cranking when the shift lever is in not in the park or neutral position.
Console mounted gear shift lever equipped vehicles commonly employ a flexible cable between the shift lever and the ignition switch which is effective to cause mechanical inhibition of the ignition switch and ignition lock cylinder to the OFF/LOCK position when the gear shift lever is out of the predetermined park position. Likewise, when the ignition switch is in the OFF/LOCK position, the cable is inhibited and the shift lever is retained in the park position. An additional flexible cable is then also used between the shift lever and a neutral start switch to electrically inhibit engine cranking when the shift lever is in not in the park or neutral position.